Propeller



E. EOENING JI. il, ffm

PRorELLER Fild-'May 19. 1921 7772 es /Bven no IN VEN TOR.

ATTORNEY;4

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Patented dan. l, i924.

narran vsal ERNEST nonnina, on YoNxEas, NEW YORK.

lraorELLEn.

Application led May 19, 1921. SerialNo 470,846.

., in the accompanying drawings a satisfactory and preferred embodiment of my invention, F ig. 1 being an end elevation of such propeller, and Fig. 2 a plan view thereof.

The particular propeller shown has three blades made in one piece with a cylindrical hub or sleeve adapted to be secured to a shaft (not shown) in any suitable manner. This hub or sleeve is indicated at A, and the i blades at B. Each of the blades is connected with the hub by a shank C disposed radially, said shanks being placed in different planes of rotation and also in different longitudinal planes, and equidistant from each other in both relations. That is to say, in angular measurement the Shanks are 120 apart, see Fig. l, and in the longitudinal direction, the central blade B is equidistant from the other two, as indicated at a in Fig. 2.

Each of the blades is bounded at its inner end by an edge 10 perpendicular to the radial axis Z) of the respective blade B and its shank C, such transverse edge extending to each side of the shank, to the same extent. The` blades comprise relatively nar row inner portions lying between said transverse edge l and two parallel longitudinal (approximately radial) edges 11 situated in planes c perpendicular to the propeller axis d. As indicated in Fig. 2,' T prefer to arrange the edges 11 of the middle blade B in the same planes of rotation (or approximately) as the adjacent edges 1l of the other blades; in other words, the edges 1l of the middle blade are exactly or approximately in planes of rotation located halfway between the plane in which the axis b of said blade rotates and the planes in which the axes b of the other blades rotate. Each of the blades further comprises a rounded outer or tip portion of greater Width than the narrow inner portion lying between the edges 11. vThe curved edge 12 of said wider portion is symmetrical to the axis b and merges into the parallel edges 1l. Preferably the width of the tip portion is such that the points e at which the middle blade B is widest, will travel in the same planes of rotation as the axes Z) of the other blades, and similarly, the two points f of the other blades which are adjacent to the middle blade, at the widest portions of said other blades. rotate in the same plane as the axis Z) of the middle blade. Vith this arrangement, the narrow portions of the individual blades rotate in different paths, that is to say, there is no overlapping of the paths of the blade portions lying between the parallel edges 11. By avoiding any overlapping of said paths, there is practically no churning action at the inner portions of the blades, and the etliciency of the propeller is thus increased considerably. This eiciency is further increased by the fact that there is practically a clear space between the transverse edges at the inner ends of the blades B, and the outer surface of the sleeve or hub A, since only the relatively small shanks C (generally of circular cross section) move in this annular space. There is thus left, between the paths of said edges 10 and the outer surface of the hub A, an annular space through which the water finds a practically unobstructed passage along the outer surface of thehub, and the resistance opposed to the progress of the ship is greatly reduced, the water streaming freely lengthwise` of the propeller shaft between the blades B and the hub A. The inner blade portions (between the edges 11') are plane, or very nearly so, while the wider tip portions are somewhat twisted, so that said tip portions form a smaller angle with the plane of rotation (perpendicular to the axis d) than such inner portions.

The entire structure shown in the drawings may be made of a single piece of metal, as by casting, but I do not restrict myself to this.

While the structure has been described as a propeller, particularly for ships navigating the water, it is also adapted for other purposes, for instance as a propeller workin@ in air, as a ventilator or fan, as a pump, or (when exposed to a current of fluid such as air or water) as a motor operated by such fluid.

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I claim as my invention:

A structure adapted for use as a propeller and for other purposes, comprising a hub, a plurality of inclined blades having their in- 5 11er ends spaced from the outer surface of the hub, and Shanks extending from the outer surface of the hub to said blades, said blades having relatively narrow inner portions with parallel side edges, and relatively wide outer portions with curved tips, the side edges of il@ which merge into said parallel edges of the narrow inner portions.

In testimony whereof I have signed this specification.

' ERNEST BOENING. 

